Drafting instrument.



N PATENTED DEC. 26 1905.

o 808511 A. 0. 0001mm.

DRAFTING IN STRUMENT.

APPLICATION FILED DEC. 31,1904

rmrrnn s rarns PATENT FFICE.

DRAFTING INSTRUMENT.

Specification of Letters Patent.

Patented Dec. 26, 1905.

Application filed December 31,1904. Serial No. 239,150.

To all whmn it may concern.-

Be it known that I, ALDEN C. COCI-IRAN, a citizen of the United States of America, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Drafting Instruments, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to certain new and useful improvements in drafting instruments, and has for its object the provision of a novel drafting instrument wherein a protractor, angle, engineers scale, architects scale, lettering-scale, and compass device are combined in one instrument.

Another object of this invention is to provide an instrument having a lettering-scale which is adapted to be used for producing different heights of letters.

The invention has for its further object the provision of an instrument which will be extremely simple in construction and comparatively inexpensive to manufacture. The instrument is particularly adapted for draftsmen and architects and aims to dispense with the number of instruments heretofore used for obtaining the results which can be obtained from my instrument.

Briefly described, my improved instrument I y is constructed of celluloid, substantially of an angular form, said instrument having two of its sides formed at an angle one to the other, while its third side is constructed upon an arc corresponding to the quadrant of a circle. The instrument is provided with a plu- Iality of apertures, which are arran ed in groups representing different heights 0 small and capital letters. The one angular edge of the instrument is provided with a plurality, of apertures which are employed for describ .ing circles and dividing a vertical line into any number of equal parts limited only by the number of holes. The side of the instru ment representing the quadrant of a circle is graduated, the graduations thereof representing ninety degrees.

The above construction will be hereinafter more fully described and then more specific ally pointed out in the claims, and referring to the drawings accompanying this application like characters of reference designate corresponding parts throughout both views, in which Figure l is a plan view of my improved instrument, and Fig. 2 is a longitudinal sectional view of the same.

To put my invention into practice, I preferably form my improved instrument of a sheet of celluloid A, such as is commonly used in the manufacture of protractors. In forming the sheet of celluloid I provide the same withtwo straight edges B and C, the one edge, B, of the sheet of celluloid or instrument lying at an angle to the other straight edge C, and these two sides form a center which can be conveniently used for many purposes by a draftsman. The other edge, D, of my instrument is described UPOII' an arc corresponding to the quadrant of a circle, and the edge is graduated to represent ninety degrees or a protractor. The angular edge B of the instrument is provided with a plurality of apertures E, which are arranged along the edge equidistant apart. These apertures are beveled, as indicated at F, and are employed for describing circles of different diameters. In using the instrument in this respect the aperture, as designated by the reference character G, is used as a center, and a suitable instrument is inserted through the aperture to engage in the paper or the material upon which it is desired to describe a circle, and a pencil is placed in one of the other apertures and the instrument moved around its center, which in this instance is the aperture G. In the accompanying drawings I have illustrated these apertures as being formed one-eighth of an inch apart, and the diameter or radius of a circle to be described having been determined the person using the instrument can describe a circle by employing a suitable instrument to center the plate A and a pencil. Should it be desired to describe a circle having a radius or diameter slightly greater than one-eighth of.v a given radius, I have provided the aperture H, which is spaced, whereby should it be used as a center for a circle the circle described will be one-sixteenth greater in diameter than a circle described by employing the apertures one-eighth of an inch apart.

The reference character I designates a plurality of groups of apertures which are formed in the plate A. The apertures are formed in groups for forming small and capital letters, and the group of apertures designated by 3 are used for forming letters three thirty-seconds of an inch in height, the group designated by 5 five thirty-seconds of an inch in Ioo height, and so on through the numerous groups which are used for forming letters from three to sixteen thirty-seconds of an inch in height. Each group of apertures is designated by a numeral representing the number of thirty-seconds part of an inch of letters formed by each group of apertures. The apertures forming each group are beveled similarly to the aperture F, and the apertures composing each group are connected together by suitable vertical lines J and horizontal lines K. These lines are preferably formed in the surface of the plate A similarly to the graduation of the protractor portion of my improved instrument.

Reference will now be had to one of the groups of apertures which are employed for group I am enabled to easily obtain the measurement designated by each aperture, and in the formation of letters the distances between the aperture N and the aperture IJ is intended to represent the height of a small letter,while the distance between the apertures M and L represent the height of a capital letter. It will be observed that the groups of apertures employed for forming letters three thirtyseconds' part of an inch in height are arranged in vertical alinement with one another, the corresponding aperture of each group alining.

Reference will now be had to that group of apertures which is employed for forming letters eleven thirty-seconds of an inch in height, this group being designated by the numeral 11. In these groups the apertures are vertically alined with one another, and I have used this arrangement to economize space, whereby it will be possible to form a large number of apertures in the instrument,which ermits of the instrument being used for forming letters of variable heights.

The numerals 3 to 16, inclusive, are referably stamped upon the sheet A for re erence purposes, and each numeral is placed directly below the groups of apertures which correspond to the measurement designated by said numeral.

From the foregoing description, taken in connection with the drawings, it will be observed that I have provided an instrument which can be used as a compass,for describing circles and curved lines, various scales to be used on a scaled drawing,for forming letters of different heights, also for obtaining the degrees of a circle, and the advantages of these combined instruments will be readilyapparent to those skilled in the art of using drafting instruments. 7

While I have herein specified celluloid as being used to form my improved instrument, I desire it to be understood that steel and other compositions can readily be employed and that the edges of said instrument may be made of a greater thickness than the body portion thereof, whereby the punching of the beveled apertures is facilitated.

It will be noted that various changes may be made in the details of construction without departing from the general spirit and scope of the invention For instance, an architects scale or an engineers scale may be arranged upon the straight edges B and C, if found desirable, and different scales on the reverse sides of the straight edges B and C may also be shown. It will alsobe noted 'that the instrument may be made of any suitable material, such as wood, steel, guttapercha, celluloid, or any other transparent material.

I/Vhat I claim, and desire to secure by Letters Patent, is

1. An instrument of the class described, said instrument being formed of celluloid or the like composition, said instrument having two angular edges and a curved edge, said curved edge being graduated, said instrument having a plurality of apertures formed therein in groups of three apertures symmetrically arranged and the various groups being com.- posed of apertures arranged at proportionate increasing distances apart, substantially as described.

2. An instrument of the class described comprising a substantially triangular sheet,

having a plurality of lines of grouped aper-v tures, the groups in each line being similarly and symmetrically arranged and groups in each of the lines being spaced apart at differently and gradually increasing distances from the groups of the other lines.

In testimony whereof I affix my signature in the presence of two witnesses.

ALDEN o. COOHRAN.

Witnesses:

E. E. POTTER, C. KLOSTERMANN. 

